Vertical distribution of radiocesium in bottom sediments of agricultural reservoirs and its impact on decontamination

Katengeza, E.*; Sanada, Yukihisa   ; Ochi, Kotaro   ; Iimoto, Takeshi*

This study aimed at evaluating the vertical distribution of radiocesium in bottom sediment core samples from 45 ponds sampled in 2015-2019 and clarifying the impact of the vertical distribution on the efficiency of decontamination by stripping the top 10 cm of bottom sediments. The relaxation mass depths and depth of sediment containing 90% of the inventory were larger than on land indicating faster downward migration of radiocesium in ponds. This may have been caused by accumulation from the ponds' catchments where radiocesium enrichment occurred. This indicates that local behavior of radiocesium in reservoirs are more important to decontamination outcomes.